Chronic methamphetamine (meth) self-administration in rats provides a translational animal model for the study of cognitive and motivational deficits of meth addiction in humans. This project consists of a multidisciplinary approach to study meth-induced cognitive and motivational dysfunctions, determine their critical neurobiological substrates in cortical glutamatergic circuitry, and reverse meth-induced changes with chronic pharmacotherapy. Specifically, we will first assess object recognition memory deficits in novel object and object-in-place recognition memory in rats with a history of chronic meth self-administration, withdrawal, and renewed drug-seeking. We hypothesize that chronic meth intake will negatively affect memory performance and that deficits will be related to altered glutamate receptors (AMPA, NMDA, mGluR2/3, and mGluR5) and glutamate receptor dependent neuron activity in the prefrontal and perirhinal cortices. We will also examine the ability of potential cognitive enhancers to reverse chronic meth-induced memory deficits by acting on glutamate receptors. We predict that chronic modafinil or an mGluR5 allosteric modulator (CDPPB) will reverse meth-induced cognitive deficits and reduce drug-seeking by acting on the aforementioned substrates. Finally, we will determine the impact of chronic meth SA on prefrontal cortex dependent attentional processing using a novel operant based attentional set-shifting task. These studies are significant in that they will provide novel insighs on chronic meth-induced changes in cognitive performance and neuroplasticity using a multifaceted assembly of behavioral, neurochemical, and neurophysiological techniques in a translationally relevant model of meth addiction. Ultimately, this project will advance our understanding of the neural substrates of cognitive deficits in meth addiction and the development of neurobiologically derived treatments for meth addiction.

Public Health Relevance

The major goals of this project are to study the neurobiology of chronic meth-induced cognitive deficits and relapse, and the attenuation of these factors by targeting cortical glutamate receptor function. We have closely aligned the animal model with important clinical issues both conceptually (e.g., cognitive deficits linked to meth addiction) and methodologically (e.g., analogous behavioral assessments). These studies will provide relevant and insightful data on the neurobiology of meth addiction and guidance to experimental and treatment approaches in human meth addicts.